// PicoClaw - Ultra-lightweight personal AI agent
// License: MIT
//
// Copyright (c) 2026 PicoClaw contributors

package ui

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
	tuicfg "github.com/sipeed/picoclaw/cmd/picoclaw-launcher-tui/config"
)

type modelsAPIResponse struct {
	Data []modelEntry `json:"data"`
}

type modelEntry struct {
	ID          string `json:"id"`
	Name        string `json:"name"`
	Description string `json:"description"`
}

func (a *App) newModelsPage(schemeName, userName, baseURL string) tview.Primitive {
	table := tview.NewTable().
		SetBorders(false).
		SetSelectable(true, false).
		SetFixed(0, 0)
	table.SetBorder(true).SetTitle(fmt.Sprintf(" Models  %s / %s ", schemeName, userName))

	var modelIDs []string

	status := tview.NewTextView().
		SetTextAlign(tview.AlignCenter).
		SetDynamicColors(true).
		SetText("[yellow]Fetching models…[-]")

	footer := hintBar(" Enter: select  ESC: back ")

	flex := tview.NewFlex().
		SetDirection(tview.FlexRow).
		AddItem(status, 1, 0, false).
		AddItem(table, 0, 1, false).
		AddItem(footer, 1, 0, false)

	apiKey := a.resolveKey(schemeName, userName)

	go func() {
		entries, err := fetchModels(baseURL, apiKey)
		a.tapp.QueueUpdateDraw(func() {
			if err != nil {
				status.SetText(fmt.Sprintf("[red]Error: %s[-]", err.Error()))
				table.SetCell(0, 0, tview.NewTableCell("(failed to load models)"))
				a.tapp.SetFocus(table)
				return
			}
			if len(entries) == 0 {
				status.SetText("[yellow]No models returned[-]")
				table.SetCell(0, 0, tview.NewTableCell("(no models available)"))
				a.tapp.SetFocus(table)
				return
			}

			status.SetText(fmt.Sprintf("[green]%d model(s) loaded[-]", len(entries)))
			for i, m := range entries {
				modelIDs = append(modelIDs, m.ID)
				table.SetCell(i, 0,
					tview.NewTableCell(fmt.Sprintf("%3d", i+1)).
						SetAlign(tview.AlignRight).
						SetTextColor(tcell.ColorGray).
						SetSelectable(false),
				)
				table.SetCell(i, 1,
					tview.NewTableCell(" "+m.ID).
						SetAlign(tview.AlignLeft).
						SetExpansion(1),
				)
			}
			a.tapp.SetFocus(table)
		})
	}()

	table.SetSelectedFunc(func(row, _ int) {
		if row < 0 || row >= len(modelIDs) {
			return
		}
		a.cfg.Provider.Current = tuicfg.ProviderCurrent{
			Scheme: schemeName,
			User:   userName,
			Model:  modelIDs[row],
		}
		a.save()
		a.goBack()
	})

	return flex
}

func (a *App) resolveKey(schemeName, userName string) string {
	for _, u := range a.cfg.Provider.Users {
		if u.Scheme == schemeName && u.Name == userName {
			return u.Key
		}
	}
	return ""
}

func fetchModels(baseURL, apiKey string) ([]modelEntry, error) {
	url := strings.TrimRight(baseURL, "/") + "/models"

	client := &http.Client{Timeout: 15 * time.Second}
	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		return nil, fmt.Errorf("build request: %w", err)
	}
	if apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+apiKey)
	}

	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(io.LimitReader(resp.Body, 512))
		return nil, fmt.Errorf("HTTP %d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
	}

	var result modelsAPIResponse
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, fmt.Errorf("decode response: %w", err)
	}
	return result.Data, nil
}