package io

import (
	"context"
	"errors"
	"fmt"
	stdio "io"
	"log/slog"
	"mime"
	"net/http"
	"strings"
	"time"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/trace"
	"git.yeij.top/AskaEth/Cyrene_v2/pkg/plugins/sdk"
)

// Compile-time assertion that httpTool implements sdk.Tool.
var _ sdk.Tool = (*httpTool)(nil)

// httpTool performs a single GET or POST request with headers, body, a timeout
// and SSRF protection, truncating the response to a size cap.
type httpTool struct {
	client       *http.Client
	allowedHosts []string
	maxBytes     int64
	log          *slog.Logger
}

func newHTTPTool(t *tools) *httpTool {
	return &httpTool{
		client:       t.client,
		allowedHosts: t.allowedHosts,
		maxBytes:     t.maxHTTPBytes,
		log:          t.log,
	}
}

// Name implements sdk.Tool.
func (h *httpTool) Name() string { return "http" }

// Description implements sdk.Tool.
func (h *httpTool) Description() string {
	return "Perform an HTTP GET or POST request with headers, body, timeout and SSRF protection."
}

// Parameters implements sdk.Tool.
func (h *httpTool) Parameters() (map[string]any, error) {
	return map[string]any{
		"type": "object",
		"properties": map[string]any{
			"method":     map[string]any{"type": "string", "enum": []any{"GET", "POST"}, "description": "HTTP method."},
			"url":        map[string]any{"type": "string", "description": "Absolute http(s) URL."},
			"headers":    map[string]any{"type": "object", "description": "Request headers."},
			"body":       map[string]any{"type": "string", "description": "Request body for POST."},
			"timeout_ms": map[string]any{"type": "integer", "description": "Per-request timeout in milliseconds."},
			"max_bytes":  map[string]any{"type": "integer", "description": "Response size cap in bytes."},
		},
		"required": []any{"url"},
	}, nil
}

// blockReason 把一次拦截归类成稳定原因码，供审计日志使用。日志只记这个码与来源主机：
// 拦截原因的具体文本（哪个 scheme、解析失败原话）会经错误返回给调用方，而错误文本本身
// 可能带着原 URL —— 那是**不进日志**的那一侧。
func blockReason(err error) string {
	switch {
	case errors.Is(err, ErrSSRF):
		return "ssrf_blocked"
	default:
		return "url_rejected"
	}
}

// Execute implements sdk.Tool.
func (h *httpTool) Execute(ctx context.Context, args any) (any, error) {
	m, ok := args.(map[string]any)
	if !ok {
		return nil, fmt.Errorf("io: http: args must be an object")
	}
	method := strings.ToUpper(argString(m, "method"))
	if method == "" {
		method = http.MethodGet
	}
	if method != http.MethodGet && method != http.MethodPost {
		return nil, fmt.Errorf("io: http: unsupported method %q", method)
	}
	rawURL := argString(m, "url")
	if strings.TrimSpace(rawURL) == "" {
		return nil, fmt.Errorf("io: http: url is required")
	}
	u, err := validateRequestURL(ctx, rawURL, h.allowedHosts)
	if err != nil {
		// 只记来源与原因码：rawURL 由模型/用户给，可能带 user:pass@ 或 ?api_key=，
		// 而日志会被采集与转贴；错误原文也不进日志 —— 解析失败时它包着 *url.Error，
		// 里面就是整条原串。
		h.log.Warn("io http: blocked request",
			"host", trace.HostOf(rawURL), "reason", blockReason(err))
		return nil, err
	}
	body := argString(m, "body")
	var reqBody stdio.Reader
	if body != "" {
		reqBody = strings.NewReader(body)
	}
	req, err := http.NewRequestWithContext(ctx, method, u.String(), reqBody)
	if err != nil {
		return nil, fmt.Errorf("io: http: build request: %w", err)
	}
	for k, v := range argStringMap(m, "headers") {
		req.Header.Set(k, v)
	}
	ct := req.Header.Get("Content-Type")
	if ct != "" {
		if _, err := validateContentType(ct); err != nil {
			return nil, err
		}
	} else if body != "" {
		req.Header.Set("Content-Type", "application/json")
	}
	if ms, ok := argInt(m, "timeout_ms"); ok && ms > 0 {
		ctx, cancel := context.WithTimeout(ctx, time.Duration(ms)*time.Millisecond)
		defer cancel()
		req = req.WithContext(ctx)
	}
	if h.client == nil {
		return nil, fmt.Errorf("io: http: no underlying client")
	}
	resp, err := h.client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("io: http: do: %w", err)
	}
	defer resp.Body.Close()
	data, truncated, err := readLimited(resp.Body, h.maxBytes)
	if err != nil {
		return nil, fmt.Errorf("io: http: read: %w", err)
	}
	ctOut, _, _ := mime.ParseMediaType(resp.Header.Get("Content-Type"))
	return map[string]any{
		"status":       resp.StatusCode,
		"content_type": ctOut,
		"body":         string(data),
		"truncated":    truncated,
	}, nil
}