package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"strings"

	"git.d-ma.be/mathias/tapir/internal/adapters/store"
)

// runShow prints the full summary for one video: text, highlights, takeaways,
// and provenance. Read-only. Usage: tapir show <video-id>.
func runShow(ctx context.Context, args []string) error {
	if len(args) != 1 || strings.TrimSpace(args[0]) == "" {
		return errors.New("usage: tapir show <video-id>")
	}
	videoID := args[0]

	s, userID, closeFn, err := openStoreFromEnv(ctx)
	if err != nil {
		return err
	}
	defer closeFn()

	row, err := s.GetSummaryByVideo(ctx, userID, videoID)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			return fmt.Errorf("no summary for video %q", videoID)
		}
		return err
	}
	return formatShow(os.Stdout, *row)
}

// formatShow renders a single summary for terminal reading. Pure: no DB, no env,
// so it is unit-testable. Empty sections are omitted rather than printed blank.
func formatShow(w io.Writer, r store.SummaryRow) error {
	var b strings.Builder

	fmt.Fprintf(&b, "%s\n", displayTitle(r))
	if d := listDate(r); d != "-" {
		fmt.Fprintf(&b, "Date:     %s\n", d)
	}
	if strings.TrimSpace(r.Channel) != "" {
		fmt.Fprintf(&b, "Channel:  %s\n", r.Channel)
	}
	if strings.TrimSpace(r.URL) != "" {
		fmt.Fprintf(&b, "URL:      %s\n", r.URL)
	}
	fmt.Fprintf(&b, "Video ID: %s\n", r.VideoID)
	fmt.Fprintf(&b, "AI:       %s\n", aiProvenance(r))

	fmt.Fprintf(&b, "\n%s\n", strings.TrimSpace(r.Summary))

	writeList(&b, "Highlights", r.Highlights)
	writeList(&b, "Takeaways", r.Takeaways)

	_, err := io.WriteString(w, b.String())
	return err
}

// aiProvenance summarises which model produced the summary and whether the local
// stack fell back to a cloud provider — the Stage-0 "is local good enough?" signal.
func aiProvenance(r store.SummaryRow) string {
	parts := orDash(r.AIProvider)
	if strings.TrimSpace(r.AIModel) != "" {
		parts += "/" + r.AIModel
	}
	if r.FallbackUsed {
		parts += " (fallback)"
	}
	return parts
}

func writeList(b *strings.Builder, heading string, items []string) {
	if len(items) == 0 {
		return
	}
	fmt.Fprintf(b, "\n%s:\n", heading)
	for _, it := range items {
		fmt.Fprintf(b, "  - %s\n", it)
	}
}