package ingest

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
)

var _ Ingester = (*SkillsIngester)(nil)

type SkillsIngester struct {
	Version string
}

func NewSkillsIngester() *SkillsIngester {
	return &SkillsIngester{Version: "skills-index/v1"}
}

func (s *SkillsIngester) SourceID() string { return "skills-catalog" }

func (s *SkillsIngester) Ingest(path string) (*IngestResult, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("read skill: %w", err)
	}
	if len(data) < 20 {
		return nil, nil
	}

	content := string(data)
	title := extractSkillName(content, path)
	summary := extractSkillSummary(content)
	tags := extractSkillTags(content)
	projects := extractProjects(tags)
	createdAt := extractCreatedAt(content)

	fp := FingerprintWithMeta(data, map[string]string{
		"source": "skills-catalog",
		"title":  title,
	})

	return &IngestResult{
		Fingerprint:     fp,
		SourceID:        s.SourceID(),
		SourcePath:      path,
		Project:         projects,
		ContentType:     ".md",
		Title:           title,
		Summary:         summary,
		CreatedAt:       createdAt,
		LineStart:       0,
		LineEnd:         len(strings.Split(content, "\n")),
		Confidence:      0.9,
		IngesterVersion: s.Version,
		Provenance: map[string]any{
			"skill_name": title,
			"tags":       tags,
			"line_count": len(strings.Split(content, "\n")),
		},
	}, nil
}

func extractSkillName(content, path string) string {
	base := filepath.Base(filepath.Dir(path))
	if base != "" && base != "." && base != "/" {
		return base
	}
	return strings.TrimSuffix(filepath.Base(path), ".md")
}

func extractSkillSummary(content string) string {
	for _, line := range strings.Split(content, "\n") {
		trimmed := strings.TrimSpace(line)
		if strings.HasPrefix(trimmed, "description:") {
			desc := strings.TrimSpace(trimmed[len("description:"):])
			if len(desc) > 200 {
				desc = desc[:200] + "..."
			}
			return desc
		}
	}
	for _, line := range strings.Split(content, "\n") {
		trimmed := strings.TrimSpace(line)
		if strings.HasPrefix(trimmed, "# ") {
			continue
		}
		if trimmed != "" && !strings.HasPrefix(trimmed, "---") {
			return truncate(trimmed, 200)
		}
	}
	return ""
}

func extractSkillTags(content string) []string {
	for _, line := range strings.Split(content, "\n") {
		trimmed := strings.TrimSpace(line)
		if strings.HasPrefix(trimmed, "tags:") {
			raw := strings.TrimSpace(trimmed[len("tags:"):])
			raw = strings.Trim(raw, "\"[]")
			var tags []string
			for _, t := range strings.Split(raw, ",") {
				t = strings.TrimSpace(t)
				t = strings.Trim(t, "\" ")
				if t != "" {
					tags = append(tags, t)
				}
			}
			return tags
		}
	}
	return nil
}

func extractProjects(tags []string) string {
	for _, t := range tags {
		if strings.HasPrefix(t, "scope:project:") {
			return strings.TrimPrefix(t, "scope:project:")
		}
		if strings.HasPrefix(t, "scope:machine:") {
			return "[machine]"
		}
	}
	return ""
}

func extractCreatedAt(content string) string {
	for _, line := range strings.Split(content, "\n") {
		trimmed := strings.TrimSpace(line)
		if strings.HasPrefix(trimmed, "created_at:") || strings.HasPrefix(trimmed, "updated_at:") {
			return strings.TrimSpace(trimmed[strings.Index(trimmed, ":")+1:])
		}
	}
	return ""
}