// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.

module http

import net.urllib
import http.chunked

const (
	max_redirects = 4
)

struct Request {
pub:
	headers2  []string
	headers  map[string]string 
	method   string
	// cookies map[string]string
	h        string
	cmd      string
	typ      string // GET POST
	data     string
	url      string
	ws_func  voidptr
	user_ptr voidptr
	verbose  bool
}

struct Response {
pub:
	text        string
	headers     map[string]string 
	status_code int
}

pub fn get(url string) ?Response {
	req := new_request('GET', url, '') or {
		return error(err)
	}
	return req.do()
}

pub fn post(url, data string) ?Response {
	req := new_request('POST', url, data) or {
		return error(err)
	}
	return req.do()
}

pub fn new_request(typ, _url, _data string) ?Request {
	if _url == '' {
		return error('bad url') 
	}
	mut url := _url
	mut data := _data
	// req.headers['User-Agent'] = 'V $VERSION'
	if typ == 'GET' && !url.contains('?') && data != '' {
		url = '$url?$data'
		data = ''
	}
	return Request {
		typ: typ
		url: url
		data: data
		ws_func: 0
		user_ptr: 0
		headers: map[string]string
	}
}

pub fn get_text(url string) string {
	resp := get(url) or { return  '' } 
	return resp.text 
} 

fn (req mut Request) free() {
	req.headers.free()
}

fn (resp mut Response) free() {
	resp.headers.free()
}

pub fn (req mut Request) add_header(key, val string) {
	// println('start add header')
	// println('add header "$key" "$val"')
	// println(key)
	// println(val)
	// h := '$key: $val'
	// println('SET H')
	// req.headers << h
	req.headers[key] = val
	// mut h := req.h
	// h += ' -H "${key}: ${val}" '
	// req.h = h
}

pub fn (req &Request) do() ?Response {
	if req.typ == 'POST' {
		// req.headers << 'Content-Type: application/x-www-form-urlencoded'
	}
	for key, val in req.headers {
		//h := '$key: $val'
	}
	url := urllib.parse(req.url) or {
		return error('http.request.do: invalid URL $req.url')
		// return Response{} //error('ff')}
	}
	is_ssl := url.scheme == 'https'
	if !is_ssl {
		return error('non https requests are not supported right now') 
	}

	// first request
	mut p := url.path.trim_left('/')
	mut u := if url.query().size > 0 { '/$p?${url.query().encode()}' } else { '/$p' }
	mut resp := ssl_do(req.typ, url.hostname(), u)
	// follow any redirects
	mut no_redirects := 0
	for resp.status_code in [301, 302, 303, 307, 308] {
		if no_redirects == max_redirects {
			return error('http.request.do: maximum number of redirects reached ($max_redirects)')
		}
		h_loc := resp.headers['Location']
		r_url := urllib.parse(h_loc) or { 
			return error('http.request.do: cannot follow redirect, location header has invalid url $h_loc')
		}
		p = r_url.path.trim_left('/')
		u = if r_url.query().size > 0 { '/$p?${r_url.query().encode()}' } else { '/$p' }
		resp = ssl_do(req.typ, r_url.hostname(), u)
		no_redirects++
	}

	return resp
}

fn parse_response(resp string) Response {
	mut headers := map[string]string
	first_header := resp.all_before('\n') 
	mut status_code := 0 
	if first_header.contains('HTTP/') {
		val := first_header.find_between(' ', ' ')
		status_code = val.int()
	}
	mut text := '' 
	// Build resp headers map and separate the body 
	mut nl_pos := 3 
	mut i := 1 
	for { 
		old_pos := nl_pos 
		nl_pos = resp.index_after('\n', nl_pos+1) 
		if nl_pos == -1 {
			break 
		} 
		h := resp.substr(old_pos + 1, nl_pos) 
		// End of headers 
		if h.len <= 1 {
			text = resp.right(nl_pos + 1) 
			break 
		} 
		i++ 
		pos := h.index(':')
		if pos == -1 {
			continue
		}
		//if h.contains('Content-Type') {
			//continue
		//}
		key := h.left(pos)
		val := h.right(pos + 2)
		headers[key] = val.trim_space()
	}
	
	if headers['Transfer-Encoding'] == 'chunked' {
		text = chunked.decode( text )
	}

	return Response {
		status_code: status_code 
		headers: headers
		text: text 
	}
}

fn build_request_headers(user_agent, method, host_name, path string) string {
	ua := if user_agent == '' { 'v' } else { user_agent }
	return '$method $path HTTP/1.1\r\n' + 
		   'Host: $host_name\r\n' + 
		   'User-Agent: $ua\r\n' +
		   'Connection: close\r\n\r\n'
}

pub fn unescape_url(s string) string {
	panic('http.unescape_url() was replaced with urllib.query_unescape()') 
}

pub fn escape_url(s string) string {
	panic('http.escape_url() was replaced with urllib.query_escape()') 
}

pub fn unescape(s string) string {
	panic('http.unescape() was replaced with http.unescape_url()') 
}

pub fn escape(s string) string {
	panic('http.escape() was replaced with http.escape_url()') 
}

type wsfn fn (s string, ptr voidptr)