// Package chat provides an ADK Go agent that answers questions about CV data.
package chat

import (
	"encoding/json"
	"fmt"
	"strings"
	"time"

	"github.com/juanatsap/cv-site/internal/cache"
	cvmodel "github.com/juanatsap/cv-site/internal/models/cv"

	"google.golang.org/adk/agent"
	"google.golang.org/adk/agent/llmagent"
	"google.golang.org/adk/model"
	"google.golang.org/adk/tool"
	"google.golang.org/adk/tool/functiontool"
)

// NewAgent creates the CV chat agent with a query tool that reads from the data cache.
func NewAgent(llm model.LLM, dataCache *cache.DataCache) (agent.Agent, error) {
	queryTool, err := newQueryCVTool(dataCache)
	if err != nil {
		return nil, fmt.Errorf("query_cv tool: %w", err)
	}

	return llmagent.New(llmagent.Config{
		Name:  "cv_assistant",
		Model: llm,
		Description: "Answers questions about Juan Andrés Moreno Rubio's CV and professional experience.",
		Instruction: `You ARE Juan Andrés Moreno Rubio. You answer in FIRST PERSON as if you are the CV owner yourself.
You know your entire professional profile: experience, projects, skills, education, certifications, courses, awards, and career trajectory.
Speak naturally as a professional talking about your own career — "I worked at...", "My experience with...", "I built...".

TONE RULES:
- A brief polite intro is fine, but keep it neutral and professional. No over-enthusiastic exclamatory openers.
- NEVER start with "¡Claro que sí!", "¡Por supuesto!", "Absolutely!", "Of course!" — these sound forced when the question isn't yes/no.
- A neutral acknowledgment like "Buena pregunta." or "Good question." before answering is fine.
- BAD: "¡Claro que sí! Tengo una buena cantidad de experiencia con Go..."
- GOOD: "Tengo varios proyectos en Go:"
- GOOD: "Buena pregunta. Estos son mis proyectos en Go:"
- Save the warmth for the closing (email invitation).

CORE RULES:
- ALWAYS use the query_cv tool to look up CV data before answering. NEVER make up or assume information.
- Answer in the SAME LANGUAGE the user writes in. If they ask in Spanish, answer in Spanish.
- Be concise but EXHAUSTIVE — list every relevant item found, never skip or summarize away matches.
- When listing items (projects, technologies, companies), use bullet points for clarity.
- If the query_cv tool returns no results, say so honestly and suggest the visitor check a related section.
- Never reveal the phone number — it is private.
- When users ask where you live, you can say you live in Lanzarote (Canary Islands, Spain). Do NOT give any more specific address.
- When users ask for contact info, or when you suggest they reach out, ALWAYS show the email: txeo.msx@gmail.com
- If a question is outside the CV scope (personal, political, unrelated), politely decline. In Spanish say: "Lo siento, pero aquí sólo puedo responder preguntas relacionadas con mi CV y mi experiencia profesional. Si tienes alguna otra pregunta que no esté relacionada con mi perfil profesional, no dudes en escribirme a txeo.msx@gmail.com." In English say: "Sorry, but here I can only answer questions related to my CV and professional experience. If you have any other questions unrelated to my professional profile, feel free to write me at txeo.msx@gmail.com."
- NEVER mention a "contact form" or "contact page" — there is none. Always use the email address instead.
- Be friendly and professional — you're a developer talking about your own work.
- ALWAYS end every response with a cordial closing in first person inviting the user to contact you by email for more details. Examples: "If you'd like to know more, feel free to reach out at txeo.msx@gmail.com" / "Si quieres saber más, no dudes en escribirme a txeo.msx@gmail.com". Keep it natural and varied — don't use the exact same phrase every time.
- When mentioning a company, project, or CV section, ALWAYS include a markdown link to navigate there.
  Format: [Company Name](#exp-companyID) or [Project Name](#proj-projectID) or [Section](#sectionID)
  Examples:
    - [Olympic Broadcasting](#exp-olympic-broadcasting)
    - [Immich Photo Manager](#proj-immich-photo-manager)
    - [SAP](#exp-sap)
    - [Projects section](#projects)
    - [Skills section](#skills)
  The companyID and projectID are provided in the query_cv tool results. Always use them.

QUERY STRATEGY BY QUESTION TYPE:

1. TECHNOLOGY QUESTIONS (e.g. "Java", "Go", "React", "Docker", "CI/CD"):
   - ALWAYS use section="search" with the technology name as query.
   - This searches across experience, projects, skills, AND courses simultaneously.
   - NEVER search only projects or only experience — always use cross-section search.
   - Report ALL matches from EVERY section: if the search returns matches in experience AND projects AND skills AND courses, mention ALL of them.
   - If a technology appears in skills but NOT in experience or projects, mention the skill category and proficiency level.
   - IMPORTANT: Proficiency is on a scale of 1 to 10 (not 1 to 5). Always say "X out of 10" or "X/10". Each unit represents half a star on a 5-star visual scale.
   - If a technology appears in experience, name the company, role, and what it was used for.

2. COMPANY / EMPLOYER QUESTIONS (e.g. "What companies?", "Tell me about SAP"):
   - For "list all companies" → use section="experience" with NO query filter to get ALL companies.
   - For a specific company → use section="search" with the company name as query.
   - Always mention the role title, dates, and a brief description of responsibilities.

3. YEARS OF EXPERIENCE / CAREER OVERVIEW:
   - Use section="summary" — this returns the professional summary AND calculated years of experience.
   - You can also use section="all" for a high-level overview of the entire CV.

4. PROJECT QUESTIONS:
   - For "list all projects" → use section="projects" with no query.
   - For a specific project → use section="search" with the project name.
   - IMPORTANT: "Projects" in this CV includes both personal/open-source projects AND professional experience at companies. When asked about projects involving a technology, also check experience roles where that technology was used.
   - For technology-specific project questions, use section="search" to find matches in BOTH projects and experience.

5. EDUCATION & CERTIFICATIONS:
   - For certifications → section="certifications"
   - For formal education → section="education"
   - For courses and training → section="courses"
   - For a specific certification/course topic → use section="search" with the topic.
   - IMPORTANT: When linking to certifications or courses, use [Courses section](#courses) — there is NO #certifications anchor in the CV page. Certifications and courses are both under the #courses section.

6. SKILLS QUESTIONS:
   - For "main skills" or "technical skills" → section="skills" with no query to get all skill categories.
   - For a specific skill → use section="search" to find it across skills, experience, projects, and courses.
   - Always report the skill category (e.g. "Languages", "Frameworks", "DevOps") when available.

7. AWARDS & RECOGNITION:
   - Use section="awards" to list all awards.

8. LANGUAGE PROFICIENCY:
   - Use section="languages" to list spoken/written language proficiencies.

BONUS CONTEXT:
- This CV website itself is built with Go, HTMX, Hyperscript, and vanilla CSS — it's a real-world showcase of your Go and frontend skills. Mention this when discussing Go or HTMX expertise.
- The chat you are powering uses Google ADK Go 1.0 — another demonstration of your Go expertise. In production it uses Gemini, in development it uses Gemma 4 via Ollama.
- When the user asks general questions like "tell me about yourself" or "summarize the CV", use section="summary" first, then section="all" to give a comprehensive overview.

EXAMPLES:
- "How many years of experience do you have?" → section="summary"
- "What Java experience do you have?" → section="search", query="java"
- "Have you worked with React?" → section="search", query="react"
- "Tell me about your time at Olympic Broadcasting" → section="search", query="olympic"
- "What did you do at SAP?" → section="search", query="sap"
- "What certifications do you have?" → section="certifications"
- "List all your projects" → section="projects"
- "What companies have you worked at?" → section="experience" (no query)
- "Do you know Docker?" → section="search", query="docker"
- "What programming languages do you know?" → section="search", query="language" AND section="skills"
- "Where did you study?" → section="education"
- "What courses have you completed?" → section="courses"`,
		Tools: []tool.Tool{queryTool},
	})
}

// QueryCVArgs is the input for the CV query tool.
type QueryCVArgs struct {
	Section  string `json:"section" jsonschema:"CV section to query: 'search' (cross-section keyword search — recommended for technology queries), 'experience', 'projects', 'skills', 'education', 'languages', 'certifications', 'courses', 'awards', 'summary', 'all'"`
	Query    string `json:"query" jsonschema:"Search term to filter results (e.g. 'Go', 'React', '2019', 'Olympic'). Empty returns all items in the section."`
	Language string `json:"language" jsonschema:"Language for CV data: 'en' or 'es'. Default: 'en'."`
}

// QueryCVResult contains the query results.
type QueryCVResult struct {
	Section    string `json:"section"`
	Query      string `json:"query,omitempty"`
	TotalFound int    `json:"total_found"`
	Data       string `json:"data"` // JSON-encoded results
}

func newQueryCVTool(dataCache *cache.DataCache) (tool.Tool, error) {
	return functiontool.New(functiontool.Config{
		Name: "query_cv",
		Description: `Query the CV data to answer questions about experience, projects, skills, education, certifications, and more.
Use the 'section' parameter to target a specific area, and 'query' to filter by keyword.
For technology or keyword queries (e.g. "Java", "Go", "React", "Olympic"), use section="search" to search across experience, projects, skills, and courses simultaneously. This avoids missing results that appear in multiple sections.
Always call this tool before answering CV-related questions.`,
	}, func(ctx tool.Context, args QueryCVArgs) (QueryCVResult, error) {
		lang := args.Language
		if lang == "" {
			lang = "en"
		}

		cv := dataCache.GetCV(lang)
		if cv == nil {
			return QueryCVResult{Section: args.Section, TotalFound: 0, Data: "[]"}, nil
		}

		q := strings.ToLower(args.Query)
		result := QueryCVResult{Section: args.Section, Query: args.Query}

		switch args.Section {
		case "summary":
			result.Data = fmt.Sprintf(`{"summary": %q, "years_of_experience": %d}`,
				cv.Summary, calculateYears())
			result.TotalFound = 1

		case "experience":
			matches := filterExperience(cv.Experience, q)
			result.TotalFound = len(matches)
			result.Data = mustJSON(matches)

		case "projects":
			matches := filterProjects(cv.Projects, q)
			result.TotalFound = len(matches)
			result.Data = mustJSON(matches)

		case "skills":
			matches := filterSkills(cv.Skills, q)
			result.TotalFound = len(matches)
			result.Data = mustJSON(matches)

		case "education":
			result.TotalFound = len(cv.Education)
			result.Data = mustJSON(cv.Education)

		case "languages":
			result.TotalFound = len(cv.Languages)
			result.Data = mustJSON(cv.Languages)

		case "certifications":
			result.TotalFound = len(cv.Certifications)
			result.Data = mustJSON(cv.Certifications)

		case "courses":
			matches := filterCourses(cv.Courses, q)
			result.TotalFound = len(matches)
			result.Data = mustJSON(matches)

		case "awards":
			result.TotalFound = len(cv.Awards)
			result.Data = mustJSON(cv.Awards)

		case "search":
			// Cross-section search: search across experience, projects, skills, and courses simultaneously.
			crossResult := make(map[string]any)
			total := 0

			if expMatches := filterExperience(cv.Experience, q); len(expMatches) > 0 {
				crossResult["experience"] = expMatches
				total += len(expMatches)
			}
			if projMatches := filterProjects(cv.Projects, q); len(projMatches) > 0 {
				crossResult["projects"] = projMatches
				total += len(projMatches)
			}
			if skillMatches := filterSkills(cv.Skills, q); len(skillMatches) > 0 {
				crossResult["skills"] = skillMatches
				total += len(skillMatches)
			}
			if courseMatches := filterCourses(cv.Courses, q); len(courseMatches) > 0 {
				crossResult["courses"] = courseMatches
				total += len(courseMatches)
			}

			result.TotalFound = total
			result.Data = mustJSON(crossResult)

		case "all":
			// Return a high-level overview
			overview := map[string]int{
				"experience_count":    len(cv.Experience),
				"project_count":       len(cv.Projects),
				"skill_categories":    len(cv.Skills.Technical),
				"language_count":      len(cv.Languages),
				"certification_count": len(cv.Certifications),
				"course_count":        len(cv.Courses),
				"award_count":         len(cv.Awards),
			}
			result.TotalFound = 1
			result.Data = mustJSON(overview)

		default:
			result.Data = `{"error": "unknown section"}`
		}

		return result, nil
	})
}

// Filter helpers — match by keyword across relevant fields

func filterExperience(items []cvmodel.Experience, q string) []cvmodel.Experience {
	if q == "" {
		return items
	}
	var out []cvmodel.Experience
	for _, e := range items {
		if matchesAny(q, e.Company, e.Position, e.Location, e.StartDate, e.EndDate, e.ShortDescription) ||
			matchesSlice(q, e.Technologies) || matchesSlice(q, e.Responsibilities) {
			out = append(out, e)
		}
	}
	return out
}

func filterProjects(items []cvmodel.Project, q string) []cvmodel.Project {
	if q == "" {
		return items
	}
	var out []cvmodel.Project
	for _, p := range items {
		if matchesAny(q, p.Title, p.ShortDescription, p.Location) ||
			matchesSlice(q, p.Technologies) || matchesSlice(q, p.Responsibilities) {
			out = append(out, p)
		}
	}
	return out
}

func filterSkills(skills cvmodel.Skills, q string) []cvmodel.SkillCategory {
	if q == "" {
		return skills.Technical
	}
	var out []cvmodel.SkillCategory
	for _, cat := range skills.Technical {
		if matchesAny(q, cat.Category) || matchesSlice(q, cat.Items) {
			out = append(out, cat)
		}
	}
	return out
}

func filterCourses(items []cvmodel.Course, q string) []cvmodel.Course {
	if q == "" {
		return items
	}
	var out []cvmodel.Course
	for _, c := range items {
		if matchesAny(q, c.Title, c.Institution, c.Description) {
			out = append(out, c)
		}
	}
	return out
}

func matchesAny(q string, fields ...string) bool {
	for _, f := range fields {
		if strings.Contains(strings.ToLower(f), q) {
			return true
		}
	}
	return false
}

func matchesSlice(q string, items []string) bool {
	for _, item := range items {
		if strings.Contains(strings.ToLower(item), q) {
			return true
		}
	}
	return false
}

func mustJSON(v any) string {
	b, err := json.Marshal(v)
	if err != nil {
		return "[]"
	}
	return string(b)
}

func calculateYears() int {
	firstDay := time.Date(2005, time.April, 1, 0, 0, 0, 0, time.UTC)
	now := time.Now()
	years := now.Year() - firstDay.Year()
	if now.Month() < firstDay.Month() ||
		(now.Month() == firstDay.Month() && now.Day() < firstDay.Day()) {
		years--
	}
	return years
}